The present invention relates to a device for the controlled translational movement of a gear shift fork for an automobile gearbox.
The present invention particularly, but not exclusively, relates to a vehicle with a hydrostatic transmission.
Numerous automobile gearbox models are already known, in which gear shifting is assisted by cylinders which actuate the gear selecting and shifting forks.
As an example, French Pat. No. FR 2844570 describes a gear selecting and shifting device for an electronically controlled gearbox of an automobile, having several forks borne by a shaft with controlled translational movement relative to the gearbox housing and allowing the engagement of a chosen gear ratio associated with one of the forks by means of a synchronization sleeve translationally connected with the fork. The device has selection components associated respectively with the forks, each made up of a small single acting hydraulic cylinder that can be controlled selectively in order to radially move a locking finger of the selected fork in a groove of the shaft in such a way as to connect the selected fork with this shaft and to move the fork translationally for the shifting of a chosen gear ratio associated with this fork. The forks are mounted on a common shaft whose translational movement can be controlled by a double acting hydraulic cylinder.